Microencapsulated coatings offer many advantages. For example, "carbonless" copy paper employs chromogenic ink capsules coated on the copy paper which rupture under typewriter or similar impact pressure to release the marking material to make a copy without the necessity of carbon paper. Such coatings usually employ "stilt" materials, or protective materials in the coating which prevent premature rupture of the microcapsules during normal handling prior to use of the copy paper in making a data record copy.
The stilt material should be slightly larger than the microcapsules, and should be as inexpensive as possible. Most inexpensive starch granules which have the desirable uniformity of shape are too small in average size to effectively eliminate smudging of typical microencapsulated ink coatings on carbonless copy paper. One material which has the desired uniformity of shape, and a large enough average particle size is arrowroot starch. However, arrowroot starch is both scarce and expensive, so substitute stilt materials have been developed.